Table 2. Data layout for a 2-stage case–control design.
| First stage | Second stage | |||
| Exposed | Unexposed | Exposed | Unexposed | |
| Cases | N11 | N10 | n11 | n10 |
| Controls | N01 | N00 | n01 | n00 |
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.